Bicycle Mechanics - VDO 3DS Computer Magnet Sensor

I have tried a search on this topic but keep getting a HTTP Status 500 error so I will ask the question.

I am having trouble getting the main trip computer to work on a VDO 3 Wireless Computer w/Cadence. The wireless Cadence works fine, but the main trip computer either does not start counting or stops/starts counting mid-ride. I have replaced all three batteries. I know the VDO 3 has a 45 second data interfence delay update but the computer stops counting for minutes or the duration of the ride. I have used a feeler gauge to set the magnet 4mm distance from the sensor and it still does not pick it up.

Will replacing the magnet with a stronger magnet such as the Sigma Sport Power Magnet help?

Thanks, Gil

Narrow the gap between the magnet and the pickup switch and see if that helps.

Yes you can use a stronger magnet if you like it can't heart that's for sure but do get it as close as possible and re-sink it remove batteries and start over. I have 3 of these units on different bikes and all work great. Make sure the magnet lined up and passes were the groove is also on the pickup.

I had problems with my first C3DS and had to have it replaced by VDO. That said, I have mine almost touching, maybe 1mm away and it works fine, I would try that. Also you have the sensor on the non drive side right?

Yes, sensor is on non-drive side. I will reset DIGI connection and position sensor and magnet to 1mm. If that does not do the trick, I will order a Sigma Sport Power Magnet or buy a Neodymium (rare earth) magnet.

Thanks for the replies.

Gil

Is the magnet aligned with the sensor -- centered and not above or below the sensor? Try sliding the magnet up or down the spoke a few millimeters.

+1 on the Sigma mag.

I had problems with my first C3DS and had to have it replaced by VDO. That said, I have mine almost touching, maybe 1mm away and it works fine, I would try that. Also you have the sensor on the non drive side right?

I had the same problem; some early production units were faulty.

Contact VDO and they will have you read the numbers off your unit. If it is one of the bad ones they will send you a new one, no questions asked.

I had the same make and model computer. I was having a lot of similar issues with it, plus batteries were dying extremely quickly. After a year, I finally gave up on it, and got a better unit from Ciclosport with altitude, gradient, and temperature (great for riding in the Swiss mountains like I do a lot), which I love and has given me zero problems. I still have the VDO, maybe I should contact them to get it replaced and put that on another bike. However, my confidence in them is now pretty low.